Electrolytic apparatus.



' W. E. GR EENAWALT.

ELECTROLYTIC APPARATUS.

APPLICATION mm mm. 11, 1912.

Patented June 29, 1915,

' LVVENTOR.

WITNESSES.- QZZM Q WIM E. GREENAWAIT, F DENVER, COLORADO.

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Specification of Letters Patent.

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Patented June 29, 191%.

Application filed January 11, 1912. Serial No. 670,837.

Toall whom it may concern Beit known that 1, WILLIAM EJGREENA wAL'r, a citizen of the United States, residing in Denver, in the county of Denver and State of Colorado, have invented certain new and useful Improvements in Electrolytic Apparatus.

It has for its object the attainment of higher anode and cathode efiiciencies and other essential advantages which are specifically pointed out in the specification.

It is well known that in electrolysis, especially with reasonably high current densities, the electrolyte in immediate contact with the electrodes may become impoverished, and deleterious results, such as decreased efficiency and inferior deposits, are sure to follow. It has been known ever since the early experiments with electrolytic processes, that rapid changing of the electrolyte in contact with the electrodes, materially diminishes these difiiculties by bringing fresh ions in contact with the electrodes at a rate correspending with the intensity of the current.

The rapid changing of the electrolyte in contact with the electrodes may be eifected by agitating the electrolyte, or, by what amounts to essentially the same thing, moving the electrodes through the electrolyte. In either case the results depend largely on the method 'of effectively carrying it out.

The difliculty is increased if a diaphragm separates the anolyte from the catholyte.

In electrolyzing halogen solutions, in a diaphragm cell, as for example a solution of cuprous chlorid, copper is deposited at the cathode and chlorin is released at the anode. Usually, except for exceedingly small current densities, the chlorin is given 01f in the uncombined state, since the evolution of chlorin is more rapid than the rate of combination, due largely to impoverishment of the anolyte in contact with the anodes. For the same reason the chlorin is not dissolved in the anolyte. If. the anolyte contains cuprous chlorid, ferrous chlorid, sulfur dioxid, or other reagent capable of being oxidized or changed from the univalent to the bivalent condition, the chemical combination with the chlorin is not ordinarily eifective because these ions are not brought in contact with-the chlorin liberated at the anode, at the same rate at which the chlorin is released. This dificulty is largely overcome by the present invention.

Referring to the accompanying drawing,

Figure 1 represents a cross section of the apparatus and Fig. 2 the corresponding plan. In these figures, one electrode is represented as being stationary or moved with a reciprocal motion, while the other electrodes are made to revolve rapidly, each on its own vertlcal axis. This is the preferred arrangement for some solutions. Fig. 3 shows a modification of Fig. 1, in which all the electrodes revolve each about its own vertical axis. This arrangement is referred in other cases. Fig. 4: shows a etail section of the electrode and preferred method of suspendin and revolving it, and Fig. 5, the correspon ing plan. r

In the figures, 1 represents an electrolytic tank, taken as a whole, 2 the cylindrical anodes revolving each about its own axis, and 3, Figs. 1 and 2, a cathode mounted on rollers 16, so that its position may be readil changed by the reciprocating mechanism 1; to insure a more uniform deposit of metal being deposited. In Fig. 3, 3 represents a revolving cathode in all respects similar to the corresponding revolving anodes. It will be understood that it is immaterial which ,is made the anode and which the cathode; that will depend upon the electrolyte and the results desired. The cylindrical rods 2, composing the anode as a whole, are suspended on asteel shaft 4, passing up through the frame 5 and 5, and suspended on ball bearings 6. The socket for the ball bearing is mounted on, and fastened to the frame, by

' means of the bolts 7 which also serves for rod and 9 a drive, such as a rope or belt, by

means of which the cylindrical electrode rod is made to revolve aboutits own vertical axis at any rate of speed desired.

In the plan, Fig. 2, are shown the electrode rods arranged in consecutive series, to form a composite electrode, acting as a whole. From this it will be seen that while the electrode as a whole, remain stationary, the individual rods composing the electrode, may be in rapid motion, and thus bring fresh electrolyte in contact with the electrodes, atany rate of speed desired.

In Fig. 2-is shown the preferred method of rotating the rods, in which the'driver, which may Be an endlessrope orbelt, passes around the driving pulley 10, then makes a half turn around the first electrode rod pul- 45 The anode r the series for that composite electrode; the rope then passes over to the other s1de and similarly drives the other rods and returns again to the original driving pulley 10. It

5 will be seen that adjacent rods rotate in op-v posite directions, while alternate'rods rotate:

1n the same direction. The driving pulley is mounted on a sliding base,.so that the driving rope may at all times be kept sutfi- 19 ciently taut. 12 is a diaphragm separating the anolyte from the catholyte, when necessary or desirable. For some work it may be dispensed with. In some'cases it may simply be a coarsely woven material to pre- 15 vent any disintegrated anode material from getting to the deposited cathode metal.

In operating the apparatus, say, in electrolyzing a cuprous chlorid solution obtained from. leaching copper ores, in which it is 2 desired to deposit the copper and regenerate the solvent, the electrolyte is introduced into the cathode compartment 14. If the diaphragms are permeable the electrolyzed -cathode solution may pass through and be- ,come the anolyte; or a separate anolyte'may flow through the anode compartment15, if a dense diaphragm is used. The. mechanisfn is then started, and the current turned on. Each anode revolves about its own vertical axis, but the combined revolving 'rods act as a composite whole so far as the electrolysis and diaphragm are concerned. Revolving rods could also be introduced into the cathode compartment, exactly similar to those .in the anode compartment, but ex-' perience has shown that revolving cathodes in the electrolysis of copper chlorid solutions appear to be more harmful than beneficial, especially if the rotation be rapid." 40. Provision is therefore only made, in this rotated, and once, set in motion, it is only.

necessary to overcome the friction, due prin- ',cipally to the electrolyte.

at the anode, and were it not for the rotation of the carbon rods, much, in fact most, of the chlorin would be given off as free gas, because it would be impossible to rapidly absorb it in the electrolyte. The

rotating rods bring the chlorin in contact with the electrolyte as rapidly as it is released, with the result that the ferrous chlorid in the solution is converted into the 6o ferric chlorid, the cuprous chlorid into the cupric chlorid, and if sulfur dioxid is used as a depolarizer it will be effectively con-.

verted into sulfuric and hydrochloric acids; at the same time free chlorin may be absorbed by the electrolyte when the sulfur Copper is de 50 posited on the cathode, and chlorin released dioxidhas been convertedinto acid and the univalent compounds converted to the bivalent condition, and thus the electrolyte is more thoroughly and more 'efiectively -regenerated. These reactions, so efiectively carried out, also materially 'reduce the necessary relectromotive force required for the electrolytic decomposition. If the electrolyte were a sulfate solution, then the anodes would be likely to becomposed of lead. It lead is used as the anode in the electrolysis of sulfate solutions, the lead, under ordinary conditions is rlapidly peroxidized and the peroxid' accum ating on the aface of the anodes'increases the resistance and decreases the efliciency. With the revolving anode rods the peroxid is detached about as rapidly as formed-and the rate of oxidation is diminished. In the electrolysis of copper sulfate, solutions it is also desirable to have revolving cathodes similar to the revolving anodes; this insures a reguline and pure deposit of copper and a high electrical efliciency for both the anode and cathode. In I other cases a stationary anode and a revolving cathode may be desired, in which case the operation would be the reverse of that describedfor the electrolysis of cuprous chlorin. Again, if both anode and cathode are made to rotate, it is immaterial which is made the anodeand which the cathode.

The invention also finds a use in the electrolysis of substances like copper matte, in which case the; matte would compose the anode, and both anode and cathode made to rotate; the anode would be'rotated to facilitate the removal of the impurities such as sulfur, and to assurea uniform diminution, and the cathode to get a pure and reguline deposit. The diaphragm would act more as a filter to keep posited copper. I

he invention is also applicable to general refining work, and insures the equal solu-. tion of all parts of the soluble anode, with the impurities from the dethe removal ofthe impurities, and even deposition. on the cathode. In such cases the diaphragm again would act more as a filter to keep the impurities in suspension in the anolyte from getting ,to' the cathode compartment and on the metal deposited.

Or in some cases, the diaphragm may be dispensed with entirely, especially if the rate of rotati n is comparatively slow. It is well known that in depositing copper, say from a sulfate solution as the electrolyte,'as the solution becomes impoverished in copper, the efliciency grows less, and the tent, without any perceptible diminution of efliciency and still obtain a reguline deposit.

In somemetallurgical work, as for example in the hydrometa llurgical methods of extracting copper from its ores, it frequently becomes necessary to remove the icofpper fromvery dilute solutions. Hitherto this has been done with iron because'electrolytic methods were too ineflicient. With the present invention this diificulty is removed owing to the enormous amount of solution broughtin contact: with the cathode, and

the small expense of rotating the cathode rods. vThe invention also finds use .inthe deposition and -regeneration of cyanid solutions in the metallurgy of gold and silver. It

finds. use in the electrodeposition' of zinc and of other metals. It also finds use in other electrolytic arts, but the apparatus has been 'sufiiciently, described to make its purpose clear, and its application to any particular process or use may be readily understood and determined. The electrodes are suspended and attached to the frame consisting of the longitudinal pieces 5 and the cross pieces 5, so that the entire frameand electrodes may be lifted out of the electrolyte tank, for inspectionor trans-- ference to another tank.

Up to the present time it has been an insurmountable 'difliculty to adapt dia phragms to rotating electrodes. I am not aware that this has ever been accomplished on a practical working basis, and'except for small porous pots made of clay. or earthenware, 1t 1s practically impossible to con-v struct a working diaphragm on curved .lines. It is claimed for this invention that all electrolytic apparatus designed on this basis retain all the simple features of'the simplest diaphragms, while realizing all the advantages-of moving electrodes or of agitating the electrolyte.

I am aware that cathodes, and bothsoluble and insoluble anodes have been rotated but 1 around a vertical axis in electrolytic work,

What I specifically,

cathode compartmentfawcomposite; 01cm rods arrange? 1. In electrolyticflapparatusgtlie amuse. [tion of an electrolyte tank; a" straight 'diai witnesses: trode composed of a series/of fi l t ml Wk) rotating about its own vertical am's, and

means for rotating the cylindrical rods of the electrode with a common driver.

2. In electrolytic apparatus the combination of a tank containing the electrolyte; a straight diaphragm dividing the tank into anode and cathodecompartments; a 'movcathode com artments; a straight reci rocating catho e, and an anode compose of a ser es of cylindrical rods arranged in a straight line, each revolving about its own vertical axis, and driven by a common driver. 1 v

5. In electrolytic apparatus the, combination of an electrolyte tank; a straight diaphragm separating the tank 'into anode and cathode compartments; moving cathode in the cathode compartment, and composite anodes on both sides of the cathode composed of cylindrical rods arranged in a straight ;line, each rotating about its own vertical axis, and driven by a common driver 1 6. In electrolytic apparatus the combination of an electrolyte tank; a straight'diaphragni dividing the tank into anode and cathode compartments; a frame over said tank; ,cylindrical. rods a ranged in a 'straightline in consecutive series suspended from the frame and forming a composite 1' electrode; revolubly mounted bearings from which the; rods are suspended; means for rotating the rods each about its own vertical axis with a common driver, and electrical connections through he"'stationary socket of the bearings to thejrevolvin electrodes.

' WILL E. GREE AWALT.

TIro'MAsG. HUGHES, fliHnmzrESmms. 

